The 1.0.0.8 version of ExtractMSn is available as a free download on our website. The program belongs to Office Tools. The actual developer of the free program is Thermo Fisher Scientific. The following version: 1.0 was the most frequently downloaded one by the program users. ExtractMSn.exe is the common file name to indicate the ExtractMSn installer.
From the developer:
For the first complexity, the occasional extra 1 Da in the precursor mass arises when Extract-MSn is used to generate the peaklist and a ’0′ is encountered. In those cases, the mass of the most abundant isotopic peak is chosen, which is the M 1 peak for precursor masses higher than about 1700 Da. Therefore, the extra 1 Da arises not from the instrument itself, but from the way Extract-MSn extracts the information
You may want to check out more software, such as eBookwise Librarian, Rapidocs Classic+ or Beam 2D, which might be similar to ExtractMSn.